The present invention relates to a method and an apparatus for producing an animation image by means of a computer, and especially to a method for producing an animation image which can display a variety of motions of objects by varying input data quantitatively.
A conventional system for producing an animation image is discussed, for instance, in "Method of Producing Animation Using Active Characters", by Tetsuya Uchiki and others, as part of a collection of papers filed to the Second NICOGRAPH Paper Contest (Shadanhojin Nippon Computer Graphics Kyokai, 1986), pp. 197 to 206. Based on the result of observation of an object present in a certain area, according to this system, an animated object selects an appropriate one of several patterns of an action model, which are provided beforehand in the form of programs, and moves in accordance with routine specified by these programs. In the production of an animation image of a barracuda attacking a school of herring, for instance, the following action models may be produced for the barracuda and the herring and the selected models are then implemented as programs.
A. Action model for the barracuda
(1) When a barracuda finds a school of herring, it starts an attack in the direction of the center of the school.
(2) Once turning to an attacking posture, it can not change its action for a length of time even if it misses the school of herring.
B. Action model for the herring
(1) When herring sense the attack of the barracuda, they select a direction for avoiding the attack based on the positional relationships they have with the barracuda.
(2) When they are not attacked or succeed in avoiding an attack, they select a direction which makes it possible to equalize the positional relationships they have with the neighboring herring as much as possible, while also taking action to form a school.
(3) When there is a possibility of interference (collision or contact) with other herring in proceeding in the direction selected in actions (1) or (2) with reference to the positional relationships they have with other herring in the vicinity, they change their direction to avoid contact.
In the conventional system for producing an animation image, as described above, an animated object perceives the type of an object present in its vicinity and, based thereon, selects a pattern of action.
We have discovered that the above-described conventional system has a problem in that the various actions corresponding to each animated object and each object present in the vicinity of the animated object present in the vicinity of the animated object must be described in the form of different programs for each different action. The conventional system has another problem in that it is difficult to represent a difference between the individual objects of the same type and also an action corresponding to an object having an intermediate property between different types of objects.